Non-alcoholic aqueous mouthwash

ABSTRACT

A non-alcoholic, aqueous mouthwash composition is provided which contains a dispersion system containing a non-ionic surfactant selected from an hydrogenated castor oil and a polyoxyethylene polyoxypropylene block copolymer having about 50% to about 90% ethylene oxide, a humectant and a cationic antimicrobial agent. The composition exhibits a homogeneous, uniform appearance and a high degree of bacterial efficacy.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a non-alcoholic, aqueous mouthwashcomposition. More particularly, the present invention relates to anon-alcoholic mouthwash composition which exhibits a homogeneous,uniform appearance and a high degree of bactericidal efficacy.

2. Description of the Art

Mouthwashes and oral rinse compositions have been used for many yearsand the art is replete with various compositions and formulations.Ordinarily, mouthwashes have been designed to clean the oral cavity,provide fresh breath and kill harmful bacteria. It is generallynecessary to kill certain oral bacteria that contribute to malodor orsecrete acidic residues which are harmful to teeth and aid in thedevelopment of gingivitis and periodontal disease.

Conventional mouthwashes contain a fairly high percentage of ethylalcohol ranging from 10% to 30% by weight of the total composition. Thisalcohol is used both as a disinfectant and as a solvent in which otheradditives such as flavoring oils, color additives, fluorides andastringents can be dissolved and then dispersed into the aqueoussolution. In fact, more than 95% of commercial mouthwash compositionscontain greater that 15% by weight alcohol. These high concentrations ofethyl alcohol are primarily used to kill oral bacteria since lowerconcentrations are generally adequate to disperse the additives into theaqueous solution.

However, the use of alcohol in mouthwash compositions has detrimental orundesirable side effects for many user groups. For example, many peoplecannot tolerate alcohol and must, for medical and health reasons, avoidthe use of mouthwash compositions containing alcohol. Further, youngchildren and persons over the age of sixty are extremely susceptible tohealth risks when ingesting large quantities of alcohol. Generally,recovering alcoholics must avoid oral contact with alcohol as well aspersons of certain religious beliefs. Last, those persons afflicted bydry-mouth syndrome or using certain medications, often prefer to avoidalcohol containing mouthwash compositions since the alcohol tends toremove moisture from the oral tissues and complicate the dry-mouthsyndrome or feeling.

Various attempts have been made at developing non-alcoholic mouthwashes.For example, U.S. Pat. No. 4,919,918 to Cole et al and U.S. Pat. No.4,971,785 to Wilson et al are directed to a non-alcoholic deliverysystem which can be used in mouthwashes. However, these patents areprimarily directed to dry compositions which are dissolved in waterimmediately prior to use. Dry compositions avoid some of the problemsassociated with alcohol-free aqueous compositions, namely the inabilityof the aqueous compositions to form homogeneous and stable products.

While there is clearly a need for a non-alcoholic mouthwash, there arefew aqueous, non-alcoholic mouthwashes in ready-to-use form commerciallyavailable which can achieve acceptable bactericidal efficacy. Onecommercial alcohol-free mouthwash is sold under the trademark AL-FREE byKeystone Research and Pharmaceutical, Inc. of Cherry Hill, N.J. Thisproduct contains water, glycerin, propylene glycol, polysorbate 20 and80, cetyl-pyridinium chloride, flavors, sweeteners, and coloring agents.However, this product does not exhibit a high level of bactericidalefficacy.

While surfactants would normally be employed to achieve dispersion ofthe water insoluble additives, their use is limited in the presentapplication. The use of various surfactants or surface active agents toachieve and maintain sufficient dispersion of the water insolublecomponents, particularly the flavoring oil, have been found to inhibitthe activity of certain antimicrobial agents. Since the use ofsurfactants is deleterious to the activity of certain antimicrobialagents and thus, to achieving acceptable bactericidal efficacy, thereare currently no known commercially available, ready-to-usealcohol-free, aqueous mouthwashes which effectively kill harmfulmicroorganisms.

Accordingly, a significant problem encountered with formulating analcohol-free mouthwash is that while the use of surfactants arenecessary to achieve proper dispersion, these surfactants typicallyinhibit the activity of the antimicrobial agent. Thus, an alcohol-freemouthwash must have the ability to achieve sufficient bactericidalefficacy while obtaining complete dispersion of the water insolublecomponents in the aqueous composition. The present invention addressesthis problem by the use of a specific dispersion system which results ina stable, homogeneous composition with good bactericidal efficacy. Morespecifically, it has been surprisingly found that certain surfactants,when used in low concentrations, can provide the necessary dispersingand stability characteristics needed in alcohol-free systems and alsowhich do not adversely affect the activity of the antimicrobial agentemployed.

SUMMARY OF THE INVENTION

According to this invention, an aqueous, non-alcoholic mouthwashcomposition is provided which contains a water-insoluble flavoring oiland an effective amount of a dispersion system comprising a non-ionicsurfactant selected from a hydrogenated castor oil and a polyoxyethylenepolypropylene block copolymer having about 50% to 90% ethylene oxide, ahumectant, and a disinfecting amount of a least one cationicantimicrobial agent, and wherein the composition has a homogeneous,uniformed appearance.

Also provided herein is a method for preparing an aqueous, non-alcoholicmouthwash composition wherein the surfactant is hydrogenated castor oilpresent in an amount of less than about 1.0% by weight of the totalcomposition comprising:

a) mixing a water-insoluble flavoring oil into a hydrogenated castor oilsurfactant to form a mixture;

b) adding a humectant to said mixture to form a first phase;

c) mixing an antimicrobial agent into water to form a second phase, and;

d) mixing the first phase into the second phase in a slow, controlledmanner so as to prevent the first phase from visually coagulating intodiscrete particles in the second phase.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an aqueous, non-alcoholic mouthwash which isintended to be used in place of alcohol-containing preparations. Thepresent mouthwash composition contains a water insoluble flavoring oiland an effective amount of a dispersion system composed of a non-ionicsurfactant selected from either a hydrogenated castor oil surfactant ora polyoxyethylene polyoxypropylene block copolymer having about 50% to90% ethylene oxide, a humectant, and an effective amount of one or morecationic antimicrobial agents.

The water-insoluble flavoring oil component can be any of the availablewell known essential oils which are suitable for use in mouthwashcompositions. Typically, the flavoring oils may be chosen from syntheticflavor oils, flavoring aromatics, oleo resins and extracts derived fromplants and the like, and combinations thereof. Illustrative examples ofsuch flavoring oils include spearmint oil, cinnamon oil, oil ofwintergreen (methyl salicylate), peppermint oil, clove oil, bay oil,eucalyptus oil, thyme oil, cedar leaf oil, oil of nutmeg, oil of sage,oil of bitter almonds and the like. Commonly used flavoring oils alsoinclude mints, such as peppermint, menthol, various fruit flavors, andcinnamon derivatives. Moreover, flavorings such as aldehydes and esterscan also be used.

The amount of flavoring oils employed is normally dependent on a numberof variables such as the flavor desired, the flavoring ingredient used,and the organoleptic strength desired. Accordingly, the amount may bevaried within the capabilities of those skilled in the art. Typically,the flavoring oils are used in amounts from about 0.05% to about 2.0% byweight of the final composition.

The hydrogenated castor oil surfactants are known non-ionic solubilizingand emulsifying agents. These products are produced by allowinghydrogenated castor oil to react with ethylene oxide. Particularly knownsurfactants are the products sold under the trademark CREMOPHOR RH byBASF Corp. of Parsippany, N.J. The main constituents of these productsare esters of hydrogenated castor oil fatty acids with oxyethylatedglycerol. In addition, they may contain polyglycol esters of thehydrogenated castor oil fatty acids and may also include freeoxyethylated glycerol and higher polyethylene glycols. The fatty acidesters of the glycerol polyethylene glycol and fatty acid esters ofpolyethylene glycol represent the hydrophobic part of the products. Thehydrophilic part of the products are the polyethylene glycols andethoxylated glycerol. The preferred CREMOPHOR products are sold underthe designations RH40 which has a saponification value of 50 to 60 and ahydroxyl value of 60 to 75, RH410 with a saponification value of 45 to55 and no significant hydroxyl value, RH455 with a saponification valueof 45 to 55 and no significant hydroxyl value, and RH60 with asaponification value of 40 to 50 and a hydroxyl value of 50 to 70. Mostpreferred is the RH grade 40.

The polyoxyethylene polyoxypropylene block copolymers are known aspoloxamer polyols and are non-ionic. The polyols comprise a centrallipophilic molecule (polyoxypropylene moiety) surrounded by sequences ofhydrophiles (oxyethylene moiety). Chemically, these copolymers can beclassified like those of polyethers or those of ether alcohols. Thesecopolymers are represented by the formula:

    HO(C.sub.2 H.sub.4 O)b(C.sub.3 H.sub.6 O)a(C.sub.2 H.sub.4 O)bH(I)

wherein a is a number which represents the moles of the lipophilic basesuch that it has a molecular weight of about 2800 to about 4000, and bis a number wherein 2xb equals the number of moles of the hydrophilicportion which constitutes about 70% to about 90% by weight of thecopolymer. Preferably, the copolymers or poloxamer polyols are of thesolid type. Examples of suitable copolymers or poloxamer polyols of thesolid type are PLURONIC F88, F98, F108 and F127 sold by BASF corp. ofParsippany, N.J. These copolymers contain a lipophilic moiety ofmolecular weight of about 2800 to about 4000 and a hydrophilic moiety ofabout 50% to 80% by weight of the copolymer. The most preferredsolubilizing agent is PLURONIC 108, with a molecular weight of about15,000. The letters and numbers of each PLURONIC copolymer identify andcharacterize the polyol. The letter indicates the physical nature of theproduct. (i.e. L=liquid, P=paste, F=solid). The last digit of the numbermultiplied by 10 represents the percentage of the part of the hydrophilein the final copolymer. The first and second digit (in the case of athree-digit number) indicates the importance of the lipophilic part ofthe copolymer. For example, the preferred copolymer, PLURONIC F108,indicates a solid body composed of about 80% ethylene oxide and a onesequence lipophile molecular weight of about 3300.

The surfactant component is used in combination with a suitablehumectant. Examples of suitable humectants include glycerin, sorbitol,and mannitol with glycerin being preferred. A suitable amount ofhumectants are employed to ensure that the final composition has thedesired degree of moistening mouth feel. Generally, the humectant ispresent in amounts from about 1.0% to 20% by weight of the finalcomposition.

The dispersion system employed in the present invention also includes adisinfecting amount of one or more cationic antimicrobial agents. Theantimicrobial agents used herein are known in the art and includecetylpyridinium chloride (CPC) and other quaternium ammonium salts usedin oral applications, domiphen bromide and combinations thereof. Thepreferred antimicrobial agent is capable of aiding the dispersion of thewater-insoluble flavoring oil in the aqueous medium while stillproviding suitable antimicrobial efficacy at low concentrations. Thepreferred antimicrobial agent is a combination of CPC and domiphenbromide in ratios of about lo to 50 parts CPC per part domiphen bromide.The antimicrobial agents used herein are present in low concentrationsfrom about 0.002% to about 0.2% by weight of the final composition.

It is important that the non-ionic surfactant employed herein be used inlow concentrations so as not to inhibit the activity of theantimicrobial agent. It has been surprisingly found that the presentsurfactants used in amounts of less than about 1.0% and, mostpreferably, in amounts of not more than 0.6% by weight of the finalcomposition can achieve the desired dispersion and stabilitycharacteristics without adversely affecting the activity of theantimicrobial agent employed. However, when the present surfactants areused in higher concentrations, the activity of the antimicrobial agentis reduced. Generally, the ratio of antimicrobial agent to surfactant ispreferably from about 1 part antimicrobial agent to about 1 to 500 partssurfactant.

Surprisingly, other surfactants commonly used in oral compositions,particularly non-ionic surfactants, do not appear to be able to achievethe desired dispersion characteristics without adversely inhibiting theactivity of the antimicrobial agent employed. For example, as shownbelow, certain polysorbitols (TWEENS) have a neutralizing ordeactivating affect on the antimicrobial agents which render thecompositions less effective at killing the harmful microorganisms.Anionic surfactants are also believe to adversely affect the cationicantimicrobial agents.

The mouthwash compositions of the present invention generally have pHwithin the range of 5.0 to 7.0. It is preferred that the pH of thesystem be slightly acidic such as between 5.5 to 6.5. A suitable bufferis employed to ensure that the final composition stays within this pHrange. Any of the well known buffers used in oral care compositions canbe employed. Illustrative examples of suitable buffers include alkalimetal salts, preferably sodium salts, such as sodium phosphate, sodiumbenzoate, sodium borate, sodium citrate, sodium phosphate and the likewith sodium phosphate monobasic and sodium phosphate dibasic orcombinations thereof being most preferred. The buffers are generallyused in amounts necessary to obtain and maintain the pH level describedabove. Typically, the buffers are present in amounts from about 0.1% to1.0% by weight of the final composition.

The sweetness of the composition can be adjusted using any of theconventional sweetening agents used in oral care applications. Examplesof suitable sweetening agents include sugars such as monosaccharides anddisaccharides and artificial sweeteners such as saccharin salts,cyclamate salts, acesulfame-K, aspartame and its derivatives, and thelike. Typically, these sweeteners will be present in amounts from about0.01% to about 2.0% by weight of the final composition depending on thespecific sweetener employed. Preferred are the saccharin salts such assodium saccharin, used in amounts from 0.05% to 0.1% by weight of thefinal composition.

Various coloring agents may also be employed in effective amounts toproduce the desired colors. The coloring agents may include natural foodcolors and dyes suitable in oral care compositions and are preferablywater-soluble. These colorings are generally known as FD&C dyes.Preferred are the water soluble blues, yellows, greens and reds such asFD&C Blue #1, FD&C Yellow #5, FD&C Green #3, and FD&C Red #3.

Finally, the present invention may also contain various other componentswhich do not inhibit the effectiveness of the dispersion system or thebactericidal efficacy of the composition. Examples of such componentsinclude, but are not limited to, fluorides, preservatives, chelatingagents and the like.

The composition of the present invention is alcohol-free and no alcoholper se is added to the present composition. By alcohol free, it is meantthat there will be less that 0.1% alcohol present and preferably lessthan about 0.01% alcohol present in the final composition. The presenceof small or trace amounts of alcohols can result from the particularflavoring oil selected which by their nature or their manufacturecontains trace amounts of alcohol.

The compositions of the present invention have a clear, homogeneous anduniform appearance and are stable under normal storage and shippingconditions. Most importantly, these compositions do not have visuallynoticeable particulates or oil suspensions floating on or in the aqueousmedium. Typically, these compositions exhibit shelf stability at roomtemperature for more than a year. Further, the mouthwash compositions ofthis invention have been shown to be highly stable in acceleratedstability tests. For example, the compositions tested exhibited novisible separation at three months in a constant environment of 37° C.

Under normal use, these compositions are contacted with the oral cavityfor between five and sixty seconds although longer periods can beemployed.

It has also been found that the dispersion system of the presentcomposition exhibits a high degree of bactericidal efficacy. Mostconventional mouthwashes rely substantially on the alcohol component inthe composition to kill the harmful microorganisms. However, the presentcompositions achieve generally comparable bactericidal efficacy in theabsence of ethyl alcohol.

As mentioned above, disinfecting amounts of an antimicrobial are used inthe present invention. As used herein "a disinfecting amount" of anantimicrobial agent is an amount which will reduce a microorganismpopulation comprising a mixture of candida albicans, escherichia coli,and stapohylococcus aureus by at least one log order in one minute. Inone embodiment of this invention, a combination of CPC and domiphenbromide used with 0.6% of PLURONIC 108 has exhibited at least three logreductions of a mixture of these microorganisms in three minutes.

The present compositions employing hydrogenated castor oil surfactantsare prepared according to the following process and are manufacturedusing conventional mixing equipment and vessels. The individualcomponents are mixed in two separate phases and the phases are addedtogether to produce the final compositions. The first phase consists ofthe buffer salts, sweeteners, and the antimicrobial agent(s). The secondphase consists of the hydrogenated castor oil surfactants, thewater-insoluble flavoring oils, and the humectant. The order in whichthe ingredients are mixed in the first phase is not critical. However,in the second phase, the water-insoluble flavoring oil is firstdispersed into the hydrogenated castor oil surfactant and then thehumectant is added to the mixture. Once the phases are well mixed, thesecond phase is slowly added to the first phase. Typically, the secondphase is added to the first phase at a rate of about four to about eightgallons per minute in order prevent the second phase from visuallycoagulating into white particles which render the mixture cloudy.

The present compositions employing polyoxyethylene polyoxypropyleneblock copolymers are prepared using the same process except the waterfrom the first phase can be added directly to the completed second phaseand the salts are added thereafter in a single processing vessel.

The present invention is further illustrated by the following examples.

Examples 1-5 were prepared with the composition as shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                   (g/100 ml)                                                                    1     2       3       4     5                                      ______________________________________                                        CREMOPHOR     .6     --      --     .6   --                                   RH40                                                                          TWEEN 20     --       .6     --    --    --                                   PLURONIC 108 --      --       .6   --    --                                   Sodiumlauryl Sulfate                                                                       --      --      --     .1   --                                   Flavoring Oil                                                                               .2      .2      .2    .2    .2                                  Glycerin Water                                                                             10.0    10.0    10.0  10.0  10.0                                 Sodium        .41     .41     .41   .41   .41                                 Monophosphate                                                                 Sodium Diphosphate                                                                          .11     .11     .11   .11   .11                                 Sodium Saccharin                                                                            .07     .07     .07   .07   .07                                 CPC           .1      .1      .1    .1    .1                                  Domiphen Bromide                                                                            .005    .005    .005  .005  .005                                FD + C Blue #1                                                                              .0005   .0005   .0005                                                                               .0005                                                                               .0005                               D + C Yellow #10                                                                            .0005   .0005   .0005                                                                               .0005                                                                               .0005                               ______________________________________                                    

Examples 1, 2 and 4 were 2 phase additions. Phase 1 was prepared bymixing the flavoring oil and surfactant components together in anemulsion. Glycerin was then added to the emulsion with rigorous mixing.Phase 2 was prepared by adding the rest of the various salts, sweeteningagents, antimicrobial agents and color agents to a predetermined amountof water. Phase 1 was then slowly added to phase 2 with rigorous mixingfor about 30 minutes.

Example 3 was also a two phase addition. However, the PLURONICsurfactant was first diluted into a 10% aqueous solution. Phase 1 wasprepared by adding the PLURONIC surfactant to water (in a 1:10 ratio)with rigorous mixing and heating to a temperature of about 60° C. Whenthe PLURONIC was completely dissolved, heating was discontinued and thesolution was cooled to 25° C. The flavoring oil was added to the cooledsolution with vigorous mixing to form an emulsion. Glycerin was thenadded to the emulsion with vigorous mixing. Phase 2 was prepared in thesame manner as in the other examples and phase 1 was added to phase 2with vigorous mixing.

Example 5 contains no surfactant. Phase 1 consisted of the flavoring oiland glycerin components mixed together. Phase 2 was prepared in the samemanner as in the examples above and phase 1 was added to phase 2 withvigorous mixing.

Each composition was then tested for its ability to kill a mixture ofmicroorganisms according to the following procedure. A simulated usemouthwash biocidal screen was performed on Examples 1-5 using sterilefetal calf serum (FCS) as the organic soil. Determination of the killrates of three opportunistic oral pathogens; s. aureus, e. coli and c.albicans, was measured after one and three minute time exposures. Theoral pathogens were prepared individually at about 2×10⁸ colony formingunits per ml (CFU ml) in phosphate buffered saline solution. An aliquotof 0.1 ml of each was added to a single centrifuge tube and diluted with25 ml of FCS to target a final concentration of about 1×10⁶ CFU/ml foreach organism. A 1.0 ml aliquot of microbe/FCS was added to 20 ml ofmouthwash or control solution contained in a 50 ml polypropylene tube.The tubes were agitated for five to ten seconds after initialinoculation and then agitated again for approximately an additional fiveseconds prior to sampling at one minute and three minutes time points.After one and three minutes exposure, 0.5 ml of the inoculated mouthwashcomposition was added to a primary neutralization tube of Dey-Engleybroth (DEB). Further DEB dilutions and plates were made from the primaryDEB tube. All plates and broth tubes were incubated aerobically at30°-35° C. for twenty-four hours, and at room temperature (20°-25° C.)for an additional forty-eight to seventy-two hours.

Plate counts were then determined to calculate reduction in CFU/ml forthe organisms. The calculated log order reductions for each compositionis shown in Table 2.

    ______________________________________                                        Ex-               Log Re-   Log Re-                                           am-  Surfactant   duction in                                                                              duction in                                                                            Visual                                    ple  (g/100 ml)   1 minute  3 minutes                                                                             Appearance                                ______________________________________                                        1.   0.6% CREMO-  <1        1.7     Homogeneous                                    PHOR                           appearance                                2.   0.6% polysorbital                                                                          1.0       2.0     Homogeneous                                    (TWEEN 20)                     appearance                                3.   0.6%         2.0       5.0     Homogeneous                                    PLURONIC 108                   appearance                                5.   No surfactant                                                                              2.5       5.4     Separate                                                                      phases                                    4.   0.1% sodium  <1        <1      Separate                                       lauryl sulphate +              phases                                         CHREMOPHOR                                                                    RH40                                                                     ______________________________________                                    

Examples 6-15 were prepared as described above with the same amounts offlavoring oil, glycerin, sodium monophosphate, sodium diphosphate,sodium sacchrin, CPC, domiphen bromide, and coloring agents with variousamounts of surfactants as shown in Table 3. Sufficient water was addedto each composition to equal 100%.

Examples 6-15 were tested for their ability to kill a mixture ofmicroorganisms using the procedure described above. The results are alsoshown in Table 3.

                  TABLE 3 *                                                       ______________________________________                                               6   7      8     9    10  11  12   13  14   15                         ______________________________________                                        PLURONIC --    --     --  --   --  1.2 0.95 0.6 0.45 --                       108                                                                           PLURONIC --    --     --  --   --  --  --   --  --   0.6                      F127                                                                          CREMO-   1.2   0.95   0.6 0.45 --  --  --   --  --   --                       PHOR RH40                                                                     CREMO-   --    --     --  --   0.6 --  --   --  --   --                       PHOR RH60                                                                     Log Re-  0.5   0.5    0.8 0.9  0.8 0.6 0.6  0.7 1.1  0.8                      ductions after                                                                1 min.                                                                        Log Re-  1.7   1.9    3.3 3.7  2.6 0.5 1.0  2.0 2.8  2.2                      ductions after                                                                3 min.                                                                        ______________________________________                                         * All compositions exhibited a homogeneous appearance                    

It is to be understood that the subject invention is not to be limitedto the above examples which have been provided to demonstrateoperability of the invention. The scope of the invention shall includeequivalent embodiments, modifications, and variations that fall withinthe scope of the attached claims.

What is claimed is:
 1. An aqueous, slightly acidic, non-alcoholicmouthwash composition made by a method, comprising:a) mixing a waterinsoluble flavoring oil in an amount of about 0.05 to about 2.0% byweight of said composition into a hydrogenated castor oil surfactant inan amount of less than about 1.0% by weight of said composition to forma mixture; b) adding, subsequently, a humectant to said mixture in anamount sufficient to form a first phase that is clear and homogeneous inappearance; c) mixing at least one cationic antimicrobial agent intowater that comprises about 0.1% to about 1.0% by weight of saidcomposition of a buffer effective to obtain a slightly acidic final pHto form a second phase; and d) mixing said first phase into said secondphase in a slow, controller manner so as to prevent said first phasefrom visually coagulating into discrete particles in said second phasewherein said mixed composition is of clear, homogeneous, stableappearance.
 2. The composition of claim 1 wherein said antimicrobialagent is a combination of cetylpyridinium chloride and domiphen bromide.3. The composition of claim 1 wherein said humectant is selected fromthe group consisting of glycerin, sorbitol, and mannitol.
 4. Thecomposition of claim 3 wherein said humectant is glycerin.
 5. Thecomposition of claim 1 wherein said hydrogenated castor oil has asaponification value of 45 to 55 and no significant hydroxyl value. 6.The composition of claim 5 wherein said hydrogenated castor oil ispresent in amounts of not more than 0.6% by weight.
 7. The compositionof claim 1 further comprising a sweetening and a coloring agent.
 8. Thecomposition of claim 1 wherein said composition can reduce thepopulation of s. aureus, e. coli and c. albicans by about three logorders after three minutes of exposure.
 9. The composition of claim 1wherein said composition does not exhibit any visual separation afterthree months at a constant temperature of 37° C.
 10. The non-alcoholicaqueous mouthwash composition of claim 15 comprising from about 70% toabout 95% water, about 0.1% to about 3.0% of a water insoluble flavoringoil, about 0.1% to about 1.0% of a surfactant that is a hydrogenatedcastor oil, about 1.0% to 20.0% of a humectant, and a disinfectingamount of at least one cationic antimicrobial agent wherein the ratio ofantimicrobial agent to surfactant is 1 part antimicrobial agent to 1 to500 parts surfactant and wherein said composition has a homogeneous,uniform appearance.
 11. The composition of claim 10 wherein saidantimicrobial agent is a combination of cetylpyridinium chloride anddomiphen bromide.
 12. The composition of claim 10 wherein saidsurfactant is present in amounts of not more than 0.6% by weight.
 13. Amethod for reducing the population of microorganisms selected from s.aureus, e. coli and c. albicans found in a mammalian oral cavitycomprising contacting said oral cavity with the composition of claim 1.14. The method of claim 13 where said composition is in contact withsaid oral cavity for a period of five to sixty seconds.
 15. The methodof claim 13 wherein the ratio of said surfactant to said antimicrobialagent is one part surfactant to 1 to 200 parts antimicrobial agent. 16.The method of claim 14 wherein said reduction is at least one log order.17. A non-alcoholic slightly acidic mouthwash composition, prepared bythe method of claim 1, comprising:water insoluble flavoring oils in anamount of about 0.1 to about 3.0% by weight of said composition; asurfactant that is a hydrogenated castor oil, in an amount of less thanabout 0.6% by weight of said composition; a humectant, in an amount ofabout 1.0 to about 20.0% by weight of said composition; an antimicrobialagent, in an effective amount, that is a combination of cetylpyridiniumchloride and domiphen bromide wherein the ratio of antimicrobial agentto surfactant in the composition is about 1 part antimicrobial agent toabout 1-500 parts surfactant; and water, in an amount of about 70 toabout 95% by weight of said composition, wherein said composition is ahomogeneous, uniform, composition in appearance.
 18. The aqueous,non-alcoholic composition of claim 1 wherein said flavor oils are about0.05 to about 2.0% by weight of said composition.
 19. An aqueousslightly acidic non-alcoholic mouthwash composition, prepared by themethod of claim 1, consisting of:flavoring oils in an amount of about0.05 to 2.0% by weight of said composition; a non-ionic surfactant thatis a hydrogenated castor oil, said surfactant present in an amount ofless than about 0.5% by weight of said composition; a humectant that isglycerin in an amount of about 1.0 to about 20.0% by weight of saidcomposition; and an antimicrobial agent that is cetylpyridinium chloridein an amount of about 0.002 to about 0.2% by weight of said composition.20. The composition of claim 19 wherein said antimicrobial agentadditionally includes domiphen bromide at a ratio of 10 to 50 parts CPCto CB.
 21. The composition of claim 19 wherein said surfactant is aboutor less than about 0.45% by weight of said composition.
 22. Thecomposition of claim 19 wherein said humectant is about 10% by weight ofsaid composition.